WO2010012587A1

WO2010012587A1 - Ethylene polymers

Info

Publication number: WO2010012587A1
Application number: PCT/EP2009/058993
Authority: WO
Inventors: Davide Balboni; Simona Esposito; Giampiero Morini; Fabrizio Piemontesi
Original assignee: Basell Polyolefine Italia S.R.L.
Priority date: 2008-08-01
Filing date: 2009-07-14
Publication date: 2010-02-04

Abstract

A process for copolymerizing ethylene, one or more non-conjugated cyclic diene and optionally one or more alpha olefins of formula CH₂=CHT wherein T is a C₁-C₂₀ alkyl radical comprising the step of contacting the monomers under polymerization conditions in the presence of a catalyst system comprising a metallocene compound of formula (I) wherein: M is titanium zirconium or hafnium; X, is a hydrogen atom, a halogen atom, a R, OR, OR'O, OSO₂CF₃, OCOR, SR, NR₂ or PR₂ group wherein R is an hydrocarbon radical and R' is a C₁-C₂₀-alkylidene, C₆-C₂₀-arylidene, C₇-C₂₀-alkylarylidene, or C₇-C₂₀-arylalkylidene radical; R¹, is a C₁-C₂₀-alkyl radical; R², R³, R⁴, R⁵, R⁶ and R⁷ are hydrogen atoms, or C₁-C₂₀ hydrocarbon radicals or two or more R², R³, R⁴, and R⁵ can also be joined to form a C₃-C₁₀ ring; L is a divalent C₁-C₄₀ hydrocarbon radical.

Description

Title

Ethylene polymers

The present invention relates to a process for obtaining copolymers containing derived units of ethylene and non conjugated cyclic diene and optionally containing derived units of one or more alpha olefins of formula CH₂=CHT wherein T is a C1-C20 alkyl radical. Said copolymers being obtained by using a class of metallocene compounds having a specific substitution pattern. Polymers based on non-conjugated cyclic dienes such as ethylene/propylene/ethylidene norbornene copolymers are those which are vulcanizable, are superior in weatherability, heat resistance and ozone resistance and are used for automobile industrial parts, industrial rubber products, insulating materials, civil and construction materials and rubber products such as gummed clothes and also widely used for materials to be blended with plastics such as a polypropylene and polystyrene.

However when non-conjugated cyclic dienes are polymerized the polymerization activity is low, furthermore the polymer obtained has low molecular weight and low content of non-conjugated cyclic dienes derived units since this class of comonomer is not easy to polymerize. US2003/0166800 relates to a class of metallocene compounds having polycyclic cyclopentadienyl ligand that can be optionally bridged only unbridged comples are exemplified. Said class of metallocene compounds are fit to be used to prepare ethylene/propylene copolymers and ethylene/ non conjugated cyclic diene/propylene terpolymers. However as shown in the comparative examples the incorporation of comonomer, the activity and the molecular weight of the obtained copolymers can be further improved.

The applicant find a class of bridged metallocene compound having a particular substitution pattern able to give in high yields ethylene and non conjugated cyclic diene copolymers having an high molecular weight and a relatively high non conjugated cyclic diene derived units content, without using an high concentration of non conjugated cyclic diene in the polymerization bath. An object of the present invention is a process for copolymerizing ethylene, one or more non- conjugated cyclic diene and optionally one or more alpha olefins of formula CH₂=CHT wherein T is a C1-C20 alkyl radical comprising the step of contacting ethylene, one or more non- conjugated cyclic diene and optionally one or more alpha olefins of formula CH₂=CHT under polymerization conditions in the presence of a catalyst system obtainable by contacting A) a metallocene compound of formula (I)

Wherein:

M is titanium zirconium or hafnium; preferably M is zirconium

X, equal to or different from each other, is a hydrogen atom, a halogen atom, a R, OR, OR'O, OSO₂CF₃, OCOR, SR, NR₂ or PR₂ group wherein R is a linear or branched, saturated or unsaturated Ci-C2o-alkyl, C3-C2o-cycloalkyl, C6-C₂o-aryl, C7-C₂o-alkylaryl or C₇-C₂o-arylalkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; and R' is a Ci-C₂o-alkylidene, C6-C₂o-arylidene, C7-C₂o-alkylarylidene, or C7-C₂o-arylalkylidene radical; preferably X is a hydrogen atom, a halogen atom, a OR'O or R group; more preferably X is chlorine or a methyl radical; R¹, equal to or different from each other, is a linear or branched, cyclic or acyclic Ci-C₂o-alkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; preferably R¹, equal to or different from each other, is a Ci-Cio-alkyl radical; more preferably R¹, equal to or different from each other, is a methyl, ethyl or isopropyl radical;

R², R³, R⁴, and R⁵, equal to or different from each other, are hydrogen atoms, or C₁-C₂0 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; two or more R , R , R , and R⁵ can also be joined to forma a C3-C₁0 ring that can be saturated or unsaturated optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; said ring can be substituted with one or more C₁-C₁₀ hydrocarbon radicals; preferably R , R , R , and R , equal to or different from each other are hydrogen atoms or linear or branched, cyclic or acyclic, Ci-C4o-alkyl, C2-C40 alkenyl, C2-C40 alkynyl, C₆-C₄o-aryl, C₇-C₄o-alkylaryl or C₇-C₄o-arylalkyl radicals, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; R and R equal to or different from each other, are hydrogen atoms, or C₁-C₂0 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; preferably R and R⁷, equal to or different from each other are hydrogen atoms or linear or branched, cyclic or acyclic, Ci-C₄o-alkyl, C₂-C₄0 alkenyl, C₂-C₄₀ alkynyl, C₆-C₄o-aryl, C₇-C₄o-alkylaryl or C₇-C₄o-arylalkyl radicals, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements;

L is a divalent C₁-C₄0 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements or a divalent silylidene radical containing up to 5 silicon atom; preferably L is a divalent bridging group selected from C1-C40 alkylidene, C3-C40 cycloalkylidene, C6-C40 arylidene, C7-C40 alkylarylidene, or C₇- C₄0 arylalkylidene radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements, or silylidene radical containing up to 5 silicon atoms such as SiMe₂, SiPli₂; preferably L is a group (Z(R")₂)_n wherein Z is a carbon or a silicon atom, n is 1 or 2 and R" is a C₁-C₂0 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; preferably R" is a linear or branched, cyclic or acyclic, Ci-C₄o-alkyl, C₂-C₄0 alkenyl, C₂-C₄0 alkynyl, C6-C₄o-aryl, C7-C₄o-alkylaryl or C7-C₄o-arylalkyl radical, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; more preferably the group (Z(R")₂)n is Si(CH₃)₂, SiPh₂, SiPhMe, SiMe(SiMe₃), CH₂, (CH₂)I, and C(CH₃)₂; even more preferably (Z(R")₂)nis Si(CH₃)₂. B) an alumoxane or a compound capable of forming an alkyl metallocene cation; and optionally

(C) an organo aluminum compound.

Preferably the metallocene of formula (I) is in the racemic form

The non-conjugated cyclic diene of the present invention is a cyclic compound having-two unsaturated bonds. This non-conjugated cyclic diene is preferably a hydrocarbon cyclic compound having preferably 6 to 20 carbon atoms and more preferably 6 to 12 carbon atoms. Examples of the non-conjugated cyclic diene of the present invention may include, though not particularly limited to, bicycle [2.2.1]hept-2-ene derivatives having an alkylidene group such as 5- ethylidenebicyclo[2.2.1]hept-2-ene (5-ethylidene-2-norbornene), 5-ethylidene-6- methylbicyclo[2.2.1]hept-2-ene, 5-ethylidene-6-ethylbicyclo[2.2.1]hept-2-ene, 5-ethylidene-6- isopropylbicyclo[2.2.1]hept-2-ene, 5-ethylidene-6-butylbicyclo[2.2.1]hept-2-ene, 5-n- propylidenebicyclo[2.2.1]hept-2-ene, 5-n-propylidene-6-methylbicyclo[2.2.1]hept-2-ene, 5-n- propylidene-6-ethylbicyclo[2.2.1]hept-2-ene, 5-n-propylidene-6-isopropylbicyclo[2.2.1]hept-2- ene,5-n-propylidene-6-butylbicyclo[2.2.1]hept-2-ene, 5-isopropylidenebicyclo[2.2.1]hept-2-ene, 5-isopropylidene-6-methylbicyclo[2.2.1]hept-2-ene, 5-isopropylidene-6-ethylbicyclo[2.2.1]hept- 2-ene, 5-isopropylidene-6-isopropylbicyclo[2.2.1]hept-2-ene and 5-isopropylidene-6- butylbicyclo[2.2.1]hept-2-ene; bicyclo[2.2.1]hept-2-ene derivatives having an alkenyl group such as 5-ethenylbicyclo[2.2.1]hept-2-ene(5-vinyl-2-norbornene), 5-propenylbicyclo[2.2.1] hept-2-ene and 5-butenylbicyclo[2.2.1]hept-2-ene; dicyclopentadiene, cyclooctadiene, and 4-vinyl-l- ciclohexene. Among these groups, bicyclo[2.2.1]hept-2-ene derivatives having a Ci-Cio alkylidene group as substituent and bicyclo[2.2.1]hept-2-ene derivatives having a Ci-Cio alkenyl group as substituent are preferable. Particularly preferred are 5-ethylidene-2-norbornene (E/Z-5- ethylidenebicyclo[2.2.1]hept-2-ene) and 5-vinyl-2-norbornene are most preferable. Examples of alpha olefins of formula CH₂=CHT wherein T is a Ci-C₂O alkyl radical are propylene, 1-butene, 1-pentene, 2-methyl-lpentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1- dodecacene. Preferred alpha olefin is propylene or 1-butene.

Preferably an object of the present invention is a process for copolymerizing ethylene, one or more non-conjugated cyclic diene and one or more alpha olefins of formula CH₂=CHT wherein T is a C1-C20 alkyl radical comprising the step of contacting ethylene, one or more non- conjugated cyclic diene and one or more alpha olefins of formula CH₂=CHT. The process according to the present invention can be carried out in a gas phase, or in a liquid phase in the presence or absence of an inert hydrocarbon solvent. The hydrocarbon solvent can either be aromatic such as toluene, or aliphatic such as propane, hexane, heptane, isobutane or cyclohexane. When the process is carried out in a liquid phase it can be in slurry, or in solution. Preferably the copolymers of the present invention are obtained by a solution process, i.e. a process carried out in liquid phase wherein the polymer is completely or partially soluble in the reaction medium.

As a general rule, the polymerization temperature is generally comprised between -100⁰C and +200⁰C preferably comprised between 0° and 160⁰C, more preferably between 20⁰C and 8O⁰C. The polymerization pressure is generally comprised between 0,5 and 100 bar. In one embodiment of the present invention in the metallocene compound of formula (I) R², R³, R , R⁵, R and R⁷ are hydrogen atoms.

In another embodiment of the present invention in the metallocene compound of formula (I) R and R⁷ are hydrogen atoms and the other substituents have the meaning specified above. In another embodiment of the present invention in the metallocene compound of formula (I) R², R , R , R and R are hydrogen atoms and the other substituents have the meaning specified above.

In another embodiment of the present invention in the metallocene compound of formula (I) R³, R⁴, R⁵, R⁶ and R⁷ are hydrogen atoms and the other substituents have the meaning specified above.

In another embodiment of the present invention in the metallocene compound of formula (I) R², R³, R⁵, R⁶ and R⁷ are hydrogen atoms and the other substituents have the meaning specified above.

In another embodiment of the present invention in the metallocene compound of formula (I) R , R³, R⁴, R⁶ and R⁷ are hydrogen atoms and the other substituents have the meaning specified above.

In another embodiment of the present invention in the metallocene compound of formula (I) R², R , are hydrogen atoms and the other substituents have the meaning specified above. In another embodiment of the present invention in the metallocene compound of formula (I) R , R⁵, are hydrogen atoms and the other substituents have the meaning specified above. In another embodiment of the present invention in the metallocene compound of formula (I) R , R , are hydrogen atoms and the other substituents have the meaning specified above. In another embodiment of the present invention in the metallocene compound of formula (I) R , R⁵, are hydrogen atoms and the other substituents have the meaning specified above. In another embodiment of the present invention in the metallocene compound of formula (I) R , R , are hydrogen atoms and the other substituents have the meaning specified above. In another embodiment of the present invention in the metallocene compound of formula (I) R , R , are hydrogen atoms and the other substituents have the meaning specified above. Alumoxanes used as component B) can be obtained by reacting water with an organo-aluminium compound of formula H_jAlU3__j or H_jAl₂Ue-_J, where U substituents, same or different, are hydrogen atoms, halogen atoms, Ci-C₂o-alkyl, C₃-C₂o-cyclalkyl, C₆-C₂o-aryl, C₇-C₂o-alkylaryl or or C7-C20- arylalkyl radical, optionally containing silicon or germanium atoms with the proviso that at least one U is different from halogen, and j ranges from 0 to 1 , being also a non-integer number. In this reaction the molar ratio of Al/water is preferably comprised between 1 : 1 and 100: 1. The molar ratio between aluminium and the metal of the metallocene generally is comprised between about 10: 1 and about 20000: 1, and more preferably between about 100:1 and about 5000:1. The alumoxanes used in the catalyst according to the invention are considered to be linear, branched or cyclic compounds containing at least one group of the type:

U

JL. wherein the substituents U, same or different, are described above. In particular, alumoxanes of the formula:

can be used in the case of linear compounds, wherein n is 0 or an integer from 1 to 40 and the substituents U are defined as above, or alumoxanes of the formula: U

(Al — O)n² can be used in the case of cyclic compounds, wherein n is an integer from 2 to 40 and the U substituents are defined as above. Examples of alumoxanes suitable for use according to the present invention are methylalumoxane (MAO), tetra-(isobutyl)alumoxane (TIBAO), tetra-(2,4,4- trimethyl-pentyl)alumoxane (TIOAO), tetra-(2,3-dimethylbutyl)alumoxane (TDMBAO) and tetra-(2,3,3-trimethylbutyl)alumoxane (TTMBAO). Particularly interesting cocatalysts are those described in WO 99/21899 and in WOO 1/21674 in which the alkyl and aryl groups have specific branched patterns. Non-limiting examples of aluminium compounds according to WO 99/21899 and WOO 1/21674 are: tris(2,3,3-trimethyl-butyl)aluminium, tris(2,3-dimethyl-hexyl)aluminium, tris(2,3-dimethyl- butyl)aluminium, tris(2,3-dimethyl-pentyl)aluminium, tris(2,3-dimethyl-heptyl)aluminium, tris(2-methyl-3-ethyl-pentyl)aluminium, tris(2-methyl-3-ethyl-hexyl)aluminium, tris(2-methyl-3- ethyl-heptyl)aluminium, tris(2-methyl-3-propyl-hexyl)aluminium, tris(2-ethyl-3-methyl- butyl)aluminium, tris(2-ethyl-3-methyl-pentyl)aluminium, tris(2,3-diethyl-pentyl)aluminium, tris(2-propyl-3-methyl-butyl)aluminium, tris(2-isopropyl-3-methyl-butyl)aluminium, tris(2-isobutyl- 3-methyl-pentyl)aluminium, tris(2,3,3-trimethyl-pentyl)aluminium, tris(2,3,3-trimethyl- hexyl)aluminium, tris(2-ethyl-3,3-dimethyl-butyl)aluminium, tris(2-ethyl-3,3-dimethyl- pentyl)aluminium, tris(2-isopropyl-3,3-dimethyl-butyl)aluminium, tris(2-trimethylsilyl- propyl)aluminium, tris(2-methyl-3-phenyl-butyl)aluminium, tris(2-ethyl-3-phenyl-butyl)aluminium, tris(2,3-dimethyl-3-phenyl-butyl)aluminium, tris(2-phenyl-propyl)aluminium, tris[2-(4-fluoro- phenyl)-propyl] aluminium, tris[2-(4-chloro-phenyl)-propyl]aluminium, tris[2-(3-isopropyl-phenyl)- propyljaluminium, tris(2-phenyl-butyl)aluminium, tris(3-methyl-2-phenyl-butyl)aluminium, tris(2- phenyl-pentyl)aluminium, tris[2-(pentafiuorophenyl)-propyl]aluminium, tris[2,2-diphenyl- ethyl] aluminium and tris [2 -phenyl-2-methyl-propyl] aluminium, as well as the corresponding compounds wherein one of the hydrocarbyl groups is replaced with a hydrogen atom, and those wherein one or two of the hydrocarbyl groups are replaced with an isobutyl group.

Amongst the above aluminium compounds, trimethylaluminium (TMA), triisobutylaluminium (TIBAL), tris(2,4,4-trimethyl-pentyl)aluminium (TIOA), tris(2,3-dimethylbutyl)aluminium (TDMBA) andtris(2,3,3-trimethylbutyl)aluminium (TTMBA) are preferred. Non-limiting examples of compounds able to form an alkylmetallocene cation are compounds of formula D⁺E^", wherein D⁺ is a Brønsted acid, able to donate a proton and to react irreversibly with a substituent X of the metallocene of formula (I) and E^" is a compatible anion, which is able to stabilize the active catalytic species originating from the reaction of the two compounds, and which is sufficiently labile to be able to be removed by an olefinic monomer. Preferably, the anion E^" comprises of one or more boron atoms. More preferably, the anion E^" is an anion of the formula BAr₄ , wherein the substituents Ar which can be identical or different are aryl radicals such as phenyl, pentafiuorophenyl or bis(trifluoromethyl)phenyl. Tetrakis-pentafluorophenyl borate is particularly preferred examples of these compounds are described in WO 91/02012. Moreover, compounds of the formula BAr₃ can conveniently be used. Compounds of this type are described, for example, in the published International patent application WO 92/00333. Other examples of compounds able to form an alkylmetallocene cation are compounds of formula BAr₃P wherein P is a substituted or unsubstituted pyrrol radicals. . These compounds are described in WO01/62764. Other examples of cocatalyst can be found in EP 775707 and DE 19917985. Compounds containing boron atoms can be conveniently supported according to the description of DE-A- 19962814 and DE-A- 19962910. All these compounds containing boron atoms can be used in a molar ratio between boron and the metal of the metallocene comprised between about 1 :1 and about 10:1; preferably 1 : 1 and 2.1; more preferably about 1: 1. Non limiting examples of compounds of formula D⁺E^" are: Tributylammoniumtetrakispentafiuorophenylaluminate, Tributylammoniumtetrakis(3,5-bis(trifiuoromethyl)phenyl)borate, Tributylammoniumtetrakis(4-fluorophenyl)borate, N,N-Dimethylbenzylammonium-tetrakispentafiuorophenylborate, N,N-Dimethylhexylammonium-tetrakispentafluorophenylborate, N,N-Dimethylaniliniumtetrakis(pentafluorophenyl)borate, N,N-Dimethylaniliniumtetrakis(pentafluorophenyl)aluminate, Di(propyl)ammoniumtetrakis(pentafluorophenyl)borate, Di(cyclohexyl)ammoniumtetrakis(pentafiuorophenyl)borate, Triphenylcarbeniumtetrakis(pentafluorophenyl)borate, Triphenylcarbeniumtetrakis(pentafluorophenyl)aluminate, Ferroceniumtetrakis(pentafluorophenyl)borate, Ferroceniumtetrakis(pentafluorophenyl)aluminate.

Organic aluminum compounds used as compound C) are those of formula H_jAlUs-, or H_jAl₂Ue_-J described above. The catalysts of the present invention can also be supported on an inert carrier.

This is achieved by depositing the metallocene compound A) or the product of the reaction thereof with the component B), or the component B) and then the metallocene compound A) on an inert support such as, for example, silica, alumina, Al-Si, Al-Mg mixed oxides, magnesium halides, styrene/divinylbenzene copolymers, polyethylene or polypropylene. The supportation process is carried out in an inert solvent such as hydrocarbon for example toluene, hexane, pentane or propane and at a temperature ranging from 0⁰C to 100⁰C, preferably the process is carried out at a temperature ranging from 25°C to 90⁰C or the process is carried out at room temperature.

A suitable class of supports which can be used is that constituted by porous organic supports functionalized with groups having active hydrogen atoms. Particularly suitable are those in which the organic support is a partially crosslinked styrene polymer. Supports of this type are described in

European application EP -633272. Another class of inert supports particularly suitable for use according to the invention is that of polyolefin porous prepolymers, particularly polyethylene.

A further suitable class of inert supports for use according to the invention is that of porous magnesium halides such as those described in International application WO 95/32995.

The polymer obtained with the present invention have preferably an ethylene derived units content ranging from 24.9 to 99.9 % by weight; a content of non-conjugated cyclic diene derived units ranging from 0.1 to 10.0 % by weight, preferably from 1.0 to 10.0 % by weight. Preferably the ethylene derived units content ranges from 45.0 to 75.0 % by weight, the non-conjugated cyclic diene derived units ranging from 2.0 to 10.0 % by weight the and a content of alpha olefins of formula CH₂=CHT derived units ranging from 15 to 53 % by weight. More preferably the ethylene derived units content ranges from 65.0 to 70.0 % by weight, the non-conjugated cyclic diene derived units ranges from 3.0 to 6.0 % by weight the and a content of alpha olefins of formula CH₂=CHT derived units ranges from 24.0 to 32.0 % by weight or the ethylene derived units content ranges from 45.0 to 55.0 % by weight, the non-conjugated cyclic diene derived units ranges from 4.0 to 9.0 % by weight the and a content of alpha olefins of formula

CH₂=CHT derived units ranging from 36.0 to 51.0 % by weight.

The following examples are for illustrative purpose and do not intend to limit the scope of the invention. Examples

Measure of Ethylene, propylene and non-conjugated diene content

ENB content was determined with Infrared spectroscopy by using a method based on a calibration straight line obtained by using the absorption bands in the region between 4482 cm-1 and 3950 cm-1 and the absorption band at 1688 cm-1.

Ethylene and propylene content were obtained with a method based on Near Infrared absorption bands at 5669cm-l and 5891 cm-1 , the resulting value is then corrected for the ENB content. The measures are carried out on a film sample obtained by molding the raw polymer with a hydraulic press (0.2 - 3 Kg/cm2) for about 30 seconds at either 160 ⁰C (ethylene/propylene determination) or 180 ⁰C (ENB determination) using an aluminium spacer of fixed thickness (0.1 - 0.2 mm).

Compounds

Rac-dimethylsilanediylbis(2-methyl-6,7dihydro-4,5-benzoindenyl)Zirconium dichloride (Al) has been synthesized according to example 5 of US 5,883,275.

(Al) Bis(-6,7-dihydro-4,5-benzoindenyl)Zirconium dichloride (Cl) has been synthesized according to example 1 of US2003/0166800.

Al(z^'-Bu)3 (TIBA) and methylalumoxane (MAO, Chemtura 30%wt/wt in toluene) were used as received.

Preparation of the catalyst system

A weighted amount of metallocene (Al) is transferred in a Schlenk flask under nitrogen. The solid is then dissolved in a quantity of MAO/TIBA toluene/cyclohexane solution (MAO/TIBA = 2 molar) to obtain a final Al/Zr ratio equal to 600 mol/mol. The MAO/TIBA solution is obtained by mixing a solution of MAO in Toluene with a cyclohexane solution of TIBA (Al = 4 g/1). This activated metallocene solution is maintained at room temperature under stirring for 12 h. After this, it can be used in polymerization and it maintains the initial polymerization over at least a week.

Examples 1-3 In a 4.5 litre jacketed stainless-steel autoclave is purged with nitrogen flow at 70 ⁰C for one hour.

Then, at 30 ⁰C, 1300 g. of technical iso-hexane, 5-ethenylbicyclo[2.2.1]hept-2-ene(5-vinyl-2- norbornene) (ENB) (amount reported in Table 1) and 4 mmol of MAO/TIB A cyclohexane solution (MAO/TIBA = 2 molar) are introduced in the autoclave.

The autoclave is closed and the temperature is raised to 58 ⁰C and ethylene and propylene

(amounts reported in Table 1 ) are added.

A measured amount (Table 1) of activated metallocene catalyst system solution is added to 5 mL of technical iso-hexane and then injected in the autoclave by nitrogen overpressure.

The internal pressure is kept constant for the entire polymerization test by feeding an ethylene/propylene mixture having nearly the same weight ratio of the terpolymer under production. On table 1 the polymerization conditions are reported.

After 30 minutes the bottom discharge valve is opened and the terpolymer solution is discharged from the autoclave into a heated steel tank and monomers and solvent are removed by feeding for

10 min hot water steam.

The terpolymer was recovered and carefully dried at 70 ⁰C under vacuum for 8 hours, the characterization data are reported in Table 2.

Table 1

* Comparative Table 2

* Comparative

Examples 4-6

Polymerization of examples 1-3 has been repeated with the difference that the polymerization temperature was 50⁰C. The polymerization conditions and the characterization of the obtained polymers are reported on Tables 3 and 4.

Table 3

* Comparative Table 4

* Comparative

The results of tables 2 and 4 clearly shows that compound Al produces polymers with better characteristics and higher amount of ENB than the polymers produced with compound Cl .

Claims

A process for copolymerizing ethylene, one or more non-conjugated cyclic diene and optionally one or more alpha olefins of formula CH₂=CHT wherein T is a C1-C20 alkyl radical comprising the step of contacting ethylene, one or more non-conjugated cyclic diene and optionally one or more alpha olefins of formula CH₂=CHT under polymerization conditions in the presence of a catalyst system obtainable by contacting:) a metallocene compound of formula (I)

(I)

Wherein:

M is titanium zirconium or hafnium;

X, equal to or different from each other, is a hydrogen atom, a halogen atom, a R, OR, OR'O, OSO₂CF₃, OCOR, SR, NR₂ or PR₂ group wherein R is a linear or branched, saturated or unsaturated Ci-C₂o-alkyl, C₃-C₂o-cycloalkyl, C₆-C₂o-aryl, C₇-C₂o-alkylaryl or C7-C₂o-aryl^alkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; and R' is a Ci-C₂o-alkylidene, C6-C₂o-arylidene,

C7-C₂o-alkylarylidene, or C7-C₂o-arylalkylidene radical;

R , equal to or different from each other, is a linear or branched, cyclic or acyclic

Ci-C₂o-alkyl radical, optionally containing heteroatoms belonging to groups 13-17 of the

Periodic Table of the Elements; preferably R , equal to or different from each other, is a

Ci-Cio-alkyl radical; more preferably R , equal to or different from each other, is a methyl, ethyl or isopropyl radical;

R , R , R , and R , equal to or different from each other, are hydrogen atoms, or C₁-C₂0 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the

Periodic Table of the Elements; two or more R , R , R , and R⁵ can also be joined to form a

C3-C₁0 ring that can be saturated or unsaturated optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; said ring can be substituted with one or more C₁-C₁₀ hydrocarbon radicals;

R and R⁷ equal to or different from each other, are hydrogen atoms, or C₁-C₂0 hydrocarbon radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements;

L is a divalent C₁-C₄₀ hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements or a divalent silylidene radical containing up to 5 silicon atoms;

B) an alumoxane or a compound capable of forming an alkyl metallocene cation; and optionally (C) an organo aluminum compound.

2. The process according to claim 1 wherein in the compound of formula (I) X is a hydrogen atom, a halogen atom, a OR'O or R group;

3. The process according to claims 1 or 2 wherein in the compound of formula (I) R², R³, R⁴, and R⁵, equal to or different from each other are hydrogen atoms or linear or branched, cyclic or acyclic, Ci-C₄o-alkyl, C₂-C₄0 alkenyl, C₂-C₄0 alkynyl, C6-C₄o-aryl, C7-C₄o-alkylaryl or C₇-C₄o-arylalkyl radicals, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements; and R⁶ and R⁷, equal to or different from each other are hydrogen atoms or linear or branched, cyclic or acyclic, Ci-C₄o-alkyl, C₂-C₄0 alkenyl, C₂-C₄0 alkynyl, C6-C₄o-aryl, C7-C₄o-alkylaryl or C7-C₄o-arylalkyl radicals, optionally containing one or more heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements.

4. The process according to anyone of claims 1-3 wherein in the compound of formula (I) L is a divalent bridging group selected from C1-C40 alkylidene, C3-C40 cycloalkylidene, C₆- C40 arylidene, C7-C40 alkylarylidene, or C7-C40 arylalkylidene radicals optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements, and silylidene radical containing up to 5 silicon atoms.

5. The process according to anyone of claims 1-4 wherein in the compound of formula (I) L is a group (Z(R")2)_n wherein Z is a carbon or a silicon atom, n is 1 or 2 and R" is a C1-C20 hydrocarbon radical optionally containing heteroatoms belonging to groups 13-17 of the Periodic Table of the Elements.

6. The process according to anyone of claims 1-5 for copolymerizing ethylene, one or more non-conjugated cyclic diene and one or more alpha olefins of formula CH₂=CHT wherein T is a C1-C20 alkyl radical comprising the step of contacting ethylene, one or more non-conjugated cyclic diene and one or more alpha olefins of formula CH₂=CHT in the presence of the catalyst system of claims 1-5.

6. The process according to anyone of claims 1-5 wherein the non-conjugated cyclic diene is preferably a hydrocarbon compound having preferably 6 to 20 carbon atoms.

7. The process according to claim 6 wherein the non-conjugated cyclic diene is selected from the group consisting of bicyclo[2.2.1]hept-2-ene derivatives having a C₁-C₁₀ alkylidene group as susbstitutent and bicyclo[2.2.1]hept-2-ene derivatives having a C₁-C₁₀ alkenyl group as susbstitutent.

8. The process according to claim 7 wherein the non-conjugated cyclic diene is selected from 5-ethylidene-2-norbornene (E/Z-5-ethylidenebicyclo[2.2.1]hept-2-ene) and 5-vinyl- 2-norbornene.

9. The process according to anyone of claims 1-8 wherein the alpha olefins of formula CH₂=CHT are selected from the group consisting of propylene, 1-butene, 1-pentene, 2- methyl-lpentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecacene.

10. The process according to anyone of claims 1-9 wherein the polymer has an ethylene derived units content ranging from 24.9 to 99.9 % by weight and a content of non- conjugated cyclic diene derived units ranging from 0.1 to 10.0 % by weight.

11. The process according to claim 10 wherein the polymer has content of non-conjugated cyclic diene derived units ranging from 1.0 to 10.0 % by weight.

12. The process according to anyone of claims 1-9 wherein the polymer has an ethylene derived units content ranging from 45.0 to 75.0 % by weight, a non-conjugated cyclic diene derived units ranging from 2.0 to 10.0 % by weight and a content of alpha olefins of formula CH₂=CHT derived units ranging from 15 to 53 % by weight.